1. Field of the Invention
The present invention relates to a molding apparatus for manufacturing a semiconductor device, and in particular, relates to a molding apparatus for encapsulating a semiconductor device having a W-CSP (Wafer-level Chip Size Package) structure and a method using the same.
2. Description of the Related Art
A semiconductor package having approximately the same size as a semiconductor chip diced from a semiconductor wafer is typically referred to as a CSP (Chip Size Package). A CSP in which semiconductor chips formed in a semiconductor wafer is packaged at the wafer level is referred to as a “W-CSP”.
In a method of manufacturing a semiconductor device by W-CSP processing, a resin-encapsulation step in which a mold is used has been known.
A method of manufacturing a semiconductor device is described in, for example, “Japanese Patent Kokai No. 2001-185568” (a document D1). While using a detachable metal mold having a first metal mold part and a second metal mold part, the semiconductor device is manufactured by resin-encapsulation of a substrate formed with semiconductor elements. The resin encapsulation of the semiconductor device is performed by applying a uniform molding pressure to the substrate.
In particular, the method of manufacturing the semiconductor device disclosed in the document D1 has the following steps.
The method includes a substrate mounting step in which the substrate is mounted on the first metal mold part, a resin mounting step in which an encapsulation resin material for encapsulating is applied to the substrate, and a resin layer forming step in which the substrate is encapsulated with the encapsulation resin material. In the resin layer forming step, a resin layer is formed by compressing the resin material between the first metal mold part and the second metal mold part so that the encapsulation resin material extends over a large area of the substrate by applying a molding pressure on the encapsulation resin material.
In the method for manufacturing the semiconductor device having the W-CSP structure while using the detachable metal mold, the encapsulation resin material is mounted on applied to a semiconductor wafer which is mounted on the second metal mold part. Therefore, there is a probability that columnar electrodes formed on the semiconductor wafer are probably deformed by the encapsulation resin material on which the molding pressure is applied.
Moreover, there is the following problem in the method. Air in a cavity of the detachable metal mold is not easily evacuated, so that air voids are prone to be generated in the encapsulation resin material of the semiconductor device. The generation of the air voids will decrease the yield rate of the semiconductor device.